The only Mainer in President Obama's cabinet will not be staying on for a second term. Karen Mills, the administrator of the U.S. Small Business Administration, announced her resignation in a letter to agency staff this morning. As Jay Field reports, Mills has spent her tenure working to promote entrepreneurship and ease the credit crunch that's been a drag on small businesses since the beginning of the recession.

Few SBA administrators, if any, faced the kinds of challenges confronting Karen Mills, when the former venture capitalist took over the agency four years ago. The country was in the early grip of the worst financial crisis since the great depression.

"Karen's moving into that position in 2009 was very, very positive," he says. "I think that was a signal just how important small business is in the United States. And Karen coming from Maine, already knowing how important small business is, brought that perspective to the administration."

At the time of her appointment, Mills had been working for years to support the growth of small companies in Maine by building business clusters focused on a specific industry or innovation.

Once in Washington, Mills shifted into crisis mode. She led an effort to cut burdensome red tape out of the SBA loan application process. And she convinced more than 1,000 community banks across the country to return to SBA lending. U.S. Sen. Susan Collins suggested to President Obama that he tap Mills to run the agency.

"She's done a very good job at a time when small businesses were having difficultites getting credit in our state. And SBA played an important role in expanding its loan guarantee program," Collins says.

During her tenure, the agency has facilitated $106 billion in lending to just under 200,000 small businesses.

Mills didn't give a reason for her departure. She'll stay on until her successor is confirmed. Then, she'll return to Brunswick, where she runs the MMP Group, a private equity firm, and her husband, Barry, serves as president of Bowdoin College.

In the interest of full disclosure, Barry Mills sits on the MPBN board of trustees.